The present invention relates to a spanner or monkey spanner to which a force can be applied in only one direction, wherein the jaws are constructed so that a force can be applied in only one direction for rotating the spanner for tightening or releasing an element such as a hexagonal head bolt or a hexagonal nut.
In general, a spanner or a monkey spanner is used when tightening or releasing a tightening element such as a hexagonal head bolt or a hexagonal nut. However since the clamping jaws of the spanner are constant in dimension, when the element to be tightened is inserted into the clamping jaws, they first should be turned a predetermined rotating angle and thereafter removed and returned to their original position and then again inserted around the bolt or nut to repeat the procedure. This creates the disadvantage whereby the working procedure becomes inconvenient and slow.